Spline auto UV not working
Viewport preview is not supported for bezier curve objects automatic texture coordinates except Object, at least for 2.7# series, this may change in future versions but for the time being it is a known limitation. Both Generated and Use UV for Mapping options are only visible while rendering in Cycles/Blender Internal, OpenGL support does not display these.

You also seem to misunderstand how to use those coordinates. If you activate Use UV for Mapping you must use UV type coordinates in your node setup, not Generated.